The transport industry relies heavily on containers, such as so-called multi-modal containers that may be conveniently be transported in ships, on trains or pulled by tractor trailers. In the particular case of the trucking industry, flatbed trailers are commonly used for carrying loads, with or without containers.
Loading and unloading of trailers and containers may benefit from the use of heavy equipment but nevertheless remains a manpower-intensive operation. Billions of dollars worth of merchandize are shipped worldwide on a daily basis. Given such numbers, rapid loading and unloading of freight vehicles is an important economical requirement.
Within large, fixed manufacturing plants and storage plants, apparatuses for loading and unloading of containers or flatbed trailers are oftentimes permanently installed, for example having their foundations embedded in a concrete floor. It becomes fairly easy to ensure that such a floor is smooth, level and nearly horizontal. Motion of such apparatuses is generally provided by use of hydraulic systems. Hydraulic systems are economical and powerful. Use of hydraulic systems provides loading equipment flexibility in terms of adapting to all kinds of loads.
On temporary sites or on outdoor sites, loading equipment is subjected to additional constraints. These apparatus may need to be installed on uneven ground or on a modest slope. It may be required to change the location of loading equipment from time to time, according to constraints of a particular application. Hydraulic systems may not be able to withstand a wide variation of outdoor temperatures, between hot summer temperatures and sub-freezing winter climates. Additionally, the use of hydraulic systems may cause environmental concerns, as even a minor oil leak may cause stoppage of loading equipment and costly site decontamination.
Therefore, there is a need for improved loading and unloading techniques enabling rapid and economical freight manipulation, in various site and weather conditions, while ensuring proper care for the environment.